#!/bin/sh
# bootstrap a xapian source tree obtained from git to produce a tree like
# you'd get from unpacking the results of "make dist"
#
copyright='
# Copyright (C) 2002,2003,2004,2005,2006,2007,2008,2009,2010,2011,2012,2013,2014,2015,2016,2017,2018,2019 Olly Betts
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License as
# published by the Free Software Foundation; either version 2 of the
# License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301
# USA
'

if [ "$1" = "--help" ] ; then
  cat <<__END__
$0 [--ftp|--http] [--download-tools=(always|ifneeded|never)] [--fetch-url-command=CMD] [--clean] [MODULE...]

The default is to bootstrap all known modules.  Any modules which have a
file called ".nobootstrap" in their top-level will be skipped.
__END__
  exit 0
fi

trap 'echo "Bootstrap failed"' EXIT
set -e

# The variables which specify the autotools to use.
autotools="AUTORECONF AUTOCONF AUTOHEADER AUTOM4TE AUTOMAKE ACLOCAL LIBTOOLIZE"

# Tool for downloading a file from a URL (currently wget, curl, and lwp-request
# are probed for in that order).  Can be specified with --fetch-url-command.
FETCH_URL_TOOL=

check_checksum() {
  checksum_=$1
  tarball_=$2

  if [ -z "$SHA256SUM_TOOL" ] ; then
    for SHA256SUM_TOOL in \
	'${SHA256SUM-sha256sum} 2>/dev/null|cut -d\  -f1' \
	'${SHASUM-shasum} -a256 2>/dev/null|cut -d\  -f1' \
	'${OPENSSL-openssl} sha256 2>/dev/null|sed "s/.* //"' \
	'' ; do
      if [ -z "$SHA256SUM_TOOL" ] ; then
	echo <<'END'
Need sha256sum or shasum or openssl installed to check SHA256 checksums.
Set environment variable SHA256SUM, SHASUM or OPENSSL if the tool isn't on
your PATH.
END
	exit 1
      fi
      # Sanity check by hashing empty input.
      r=`:|eval "$SHA256SUM_TOOL"`
      [ X"$r" != Xe3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855 ] || break
    done
  fi
  r=`< $tarball_ eval "$SHA256SUM_TOOL"`
  if [ X"$r" != X"$checksum_" ] ; then
    echo "$tarball_: computed SHA256 checksum did NOT match"
    echo "computed: $r with $SHA256SUM_TOOL"
    echo "expected: $checksum_"
    ls -l $tarball_
    file $tarball_ || true
    mv "$tarball_" "$tarball_.$r"
    echo "Renamed $tarball_ to $tarball_.$r"
    exit 1
  fi
}

check_at_least() {
  # This function is expected to be used in 'if' so we can't rely on set -e
  # being in effect here.
  v1=$1
  v2=$2
  save_IFS=$IFS
  IFS=.
  set x $v1
  for v in $v2 ; do
    shift
    if [ "$1" != "$v" ] ; then
      if [ -z "$1" ] || [ "$1" -lt "$v" ] ; then
	IFS=$save_IFS
	return 1
      fi
      break
    fi
  done
  IFS=$save_IFS
  return 0
}

need_to_build() {
  # This function is expected to be used in 'if' so we can't rely on set -e
  # being in effect here.
  package=$1
  version=$2
  binary=$3

  case $download_tools in
    always) ;;
    never)
      return 1
      ;;
    *)
      if [ -n $binary ] ; then
	if [ -s "../patches/$package/series" ] ; then
	  echo "There are patches to apply to $package so it has to be built"
	else
	  # Check if a new enough version is already installed.
	  version_installed=`"$binary" --version 2>/dev/null|sed '1,1 s/.* //p;d'`
	  if [ -n "$version_installed" ] ; then
	    # Fast track equality.
	    if [ "$version_installed" = "$version" ] ; then
	      echo "$binary $version_installed installed, exactly what's needed"
	      return 1
	    fi
	    if check_at_least "$version_installed" "$version" ; then
	      echo "$binary $version_installed installed >= $version required"
	      return 1
	    fi
	  fi
	fi
      fi
      ;;
  esac
  return 0
}

lazy_build() {
  package=$1
  version=$2
  basename=$package-$version
  ext=$3
  checksum=$4

  if [ "$ext" = "tar.xz" ] ; then
    if [ -z "$xz_ok" ] ; then
      if ${XZ-xz} --version > /dev/null 2>&1 ; then
	xz_ok=1
      else
	xz_ok=0
      fi
    fi
    if [ "$xz_ok" = 0 ] ; then
      shift 2
      ext=$3
      checksum=$4
    fi
  fi
  if [ "$ext" = "tar.bz2" ] ; then
    if [ -z "$bz2_ok" ] ; then
      # bzip2 --version doesn't exit with code 0 in upstream version (though
      # Debian at least patch this bug), so use --help to check it.
      if bzip2 --help > /dev/null 2>&1 ; then
	bz2_ok=1
      else
	bz2_ok=0
      fi
    fi
    if [ "$bz2_ok" = 0 ] ; then
      shift 2
      ext=$3
      checksum=$4
    fi
  fi
  tarball=$basename.$ext
  case $basename in
    *[24680][a-z]) basename=`echo "$basename"|sed 's/[a-z]$//'` ;;
  esac

  # Create the stamp file in INST so that rerunning bootstrap after
  # "rm -rf INST" recovers nicely.
  stamp=../INST/$package.stamp
  out_of_date=

  # Download the tarball if required.
  if [ ! -f "$tarball" ] ; then
    main_tarball=
    # Older git versions don't support "git worktree", so discard stderr and
    # then we'll skip the worktree handling because main_worktree_dir will
    # be empty.
    main_worktree_dir=`git worktree list --porcelain 2>/dev/null|sed 's/^worktree //;q'`
    if [ -n "$main_worktree_dir" ] ; then
      # Canonicalise main_worktree_dir before comparing with pwd.
      main_worktree_dir=`cd "$main_worktree_dir" && pwd`
      if [ "$main_worktree_dir/BUILD" != "`pwd`" ] ; then
	# If main_tarball is set non-empty, then we're a linked worktree.
	main_tarball=$main_worktree_dir/BUILD/$tarball
      fi
    fi
    if [ -n "$main_tarball" ] && [ -f "$main_tarball" ] ; then
      # Don't re-download the tarball if the main worktree already has it.
      tarball=$main_tarball
    else
      if [ -z "$FETCH_URL_TOOL" ] ; then
	if ${WGET-wget} --version > /dev/null 2>&1 ; then
	  FETCH_URL_TOOL="${WGET-wget} -O-"
	elif ${CURL-curl} --version > /dev/null 2>&1 || [ "$?" = 2 ] ; then
	  # curl --version exits with code 2 (~7.18.2) or 0 (7.35.0).
	  # -L is needed to follow HTTP redirects.
	  FETCH_URL_TOOL="${CURL-curl} -L"
	elif ${LWP_REQUEST-lwp-request} -v > /dev/null 2>&1 || [ "$?" = 9 -o "$?" = 255 ] ; then
	  # lwp-request -v exits with code 9 (5.810) or 255 (6.03)
	  FETCH_URL_TOOL="${LWP_REQUEST-lwp-request} -mGET"
	else
	  cat <<END >&2
Neither wget nor curl nor lwp-request found - install one of them or if already
installed, set WGET, CURL or LWP_REQUEST to the full path.  Alternatively,
download $url
to directory `pwd`
then rerun this script.
END
	  exit 1
	fi
      fi
      url="https://github.com/xapian/xapian-dev-deps/releases/download/current/$tarball"
      case $basename in
      file-*)
	case $download_protocol in
	  ftp) url="ftp://ftp.astron.com/pub/file/$tarball" ;;
	  # We used to use http://fossies.org/ but that now redirects to https.
	esac ;;
      *[13579][a-z])
	# GNU alpha release
	case $download_protocol in
	  ftp) url="ftp://alpha.gnu.org/gnu/$package/$tarball" ;;
	  http) url="http://alpha.gnu.org/gnu/$package/$tarball" ;;
	esac ;;
      *)
	case $download_protocol in
	  ftp) url="ftp://ftp.gnu.org/gnu/$package/$tarball" ;;
	  http) url="http://ftpmirror.gnu.org/$package/$tarball" ;;
	esac ;;
      esac
      case $download_protocol,$url in
	http,https:*)
	  echo "warning: No http: link for $tarball available, using https:"
	  ;;
      esac

      # Keep the tarball under a quarantined name until we've verified its
      # checksum.  Once verified, if this is a linked git worktree we save
      # the tarball in the main worktree's BUILD directory so that it can
      # be shared with other worktrees.
      if [ -n "$main_tarball" ] ; then
	tarball=$main_tarball
      fi
      quarantined_tarball=$tarball-quarantine.$$
      rm -f "$quarantined_tarball"
      echo "Downloading <$url>"
      $FETCH_URL_TOOL "$url" > "$quarantined_tarball" || exit $?
      check_checksum "$checksum" "$quarantined_tarball"
      mv "$quarantined_tarball" "$tarball"

      # Force a build.
      out_of_date=force
    fi
  fi

  if [ -z "$out_of_date" ] ; then
    if [ -f "$stamp" ] ; then
      # Check if the tarball or the patches we're applying have changed since
      # the existing build.
      out_of_date=`find "$tarball" ../patches/"$package"/* -newer "$stamp" -print 2> /dev/null||true`
    else
      out_of_date=force
    fi
  fi

  if [ -n "$out_of_date" ] ; then
    # Verify the tarball's checksum before building it.  We now check at
    # download time, but older versions of bootstrap didn't, and this also
    # protects a user who manually downloads a tarball (which we suggest as an
    # option if wget, curl, etc aren't found).
    check_checksum "$checksum" "$tarball"

    case $tarball in
      */*) ;; # Only expire tarballs from the main worktree.
      *)
	case `git worktree list --porcelain|grep -c '^worktree '` in
	  1|0)
	    # Remove tarballs of other versions if there's only one worktree, or if
	    # using git < 2.5 (before worktrees were added).
	    for f in "$package"-* ; do
	      [ "$f" = "$tarball" ] || rm -rf "$f"
	    done
	    ;;
	esac
	;;
    esac

    case $ext in
    tar.xz)
      ${XZ-xz} -dc "$tarball"| tar xf - || exit $? ;;
    tar.bz2)
      bzip2 -dc "$tarball"| tar xf - || exit $?  ;;
    *)
      gzip -dc "$tarball"| tar xf - || exit $? ;;
    esac

    cd "$basename" || exit $?

    series="../../patches/$package/series"
    if [ ! -f "$series" ] ; then
      cat <<END >&2
No patch series file 'patches/$package/series' - if there are no patches,
this should just be an empty file.
END
      exit 1
    fi
    if [ -s "$series" ] ; then
      echo "Applying patches from $package/series"
      sed -n 's/[	 ]*\(#.*\)\?$//;/./p' "$series" | \
	  while read p ; do
	echo "Applying patch $package/$p"
	patch -p1 < "../../patches/$package/$p" || exit $?
      done
    fi

    echo "Configuring $package"
    if test -n "$AUTOCONF" ; then
      ./configure --prefix "$instdir" AUTOCONF="$AUTOCONF" || exit $?
    else
      ./configure --prefix "$instdir" || exit $?
    fi
    echo "Building $package"
    make || exit $?
    echo "Installing $package"
    make install || exit $?
    echo "Done installing $package"
    cd .. || exit $?
    rm -rf "$basename" || exit $?

    touch "$stamp" || exit $?
  fi
  return 0
}

handle_git_external() {
  path=$1
  if [ ! -f "$path/.nobootstrap" ] ; then
    rev=$2
    url=$3
    if [ ! -d "$path" ] ; then
      git clone --no-checkout -- "$url" "$path"
    elif (cd "$path" && git reflog "$rev" -- 2>/dev/null) ; then
      : # Already have that revision locally
    else
      (cd "$path" && git fetch)
    fi
    (cd "$path" && git checkout "$rev")
  fi
}

update_config() {
  from=$1
  to=$2
  ts_from=`perl -ne '/^timestamp=(\W?)([-\d]+)$1/ and do {$_=$2;y/-//d;print;exit}' "$from"`
  ts_to=`perl -ne '/^timestamp=(\W?)([-\d]+)$1/ and do {$_=$2;y/-//d;print;exit}' "$to"`
  if [ "$ts_from" -gt "$ts_to" ] ; then
     echo "Updating $to ($ts_to) with $from ($ts_from)"
     # rm first in case the existing file is a symlink.
     rm -f "$to"
     cp "$from" "$to"
  fi
}

update_bootstrap_sticky_opts() {
  arg=$1
  case $arg in
    *[^-A-Za-z0-9_+=:@/.,]*)
      # Quote for the shell and escape $ to $$ for make.
      bootstrap_sticky_opts="$bootstrap_sticky_opts '"`echo "$arg"|sed "s/'/'\\\\\\''/g;"'s/[$]/\\\\$\\\\$/g'`"'"
      ;;
    *)
      bootstrap_sticky_opts="$bootstrap_sticky_opts $arg"
      ;;
  esac
}

curdir=`pwd`

# cd to srcdir if we aren't already there.
srcdir=`echo "$0"|sed 's!/*[^/]*$!!'`
case $srcdir in
  ""|.)
    srcdir=. ;;
  *)
    cd "$srcdir" ;;
esac

# Commit hash to pass to handle_git_external for swig.  Equivalent to
# SWIG 4.0.1.
swig_git_commit_hash=1e36f51346d95f8b9848e682c2eb986e9cb9b4f4

# Commit hashes to use for common in omega and letor respectively:
omega_common_commit_hash=c65fd56b6ddd11894253b16bc1d0701ff6835672
letor_common_commit_hash=c65fd56b6ddd11894253b16bc1d0701ff6835672

if [ ! -r .git ] ; then
  echo "$0: '.git' not found - this script should be run from a git repo cloned"
  echo "from git://git.xapian.org/xapian or a mirror of it"
  exit 1
fi

for emptydir in xapian-applications/omega/m4 xapian-bindings/m4 xapian-letor/m4 ; do
  if test -d "$emptydir" ; then
    :
  else
    parent=`echo "$emptydir"|sed 's,/[^/]*$,,'`
    if test -d "$parent" ; then
      mkdir "$emptydir"
    fi
  fi
done

if [ -f .git ] ; then
  : # Looks like we're in a git worktree.
else
  if [ -f .git/info/exclude ] ; then
    sed '/^\(swig\|xapian-applications\/omega\/common$\)/d' .git/info/exclude > .git/info/exclude~
  else
    [ -d .git/info ] || mkdir .git/info
  fi
  cat <<END >> .git/info/exclude~
swig
xapian-applications/omega/common
xapian-letor/common
END
  if [ -f .git/info/exclude ] &&
     cmp -s .git/info/exclude~ .git/info/exclude ; then
    rm .git/info/exclude~
  else
    mv .git/info/exclude~ .git/info/exclude
  fi
fi

# If this tree is checked out from the github mirror, use the same access
# method for other things checked out from github (e.g. swig) so we avoid
# firewall issues.  If there's no default remote, the git config command
# will exit with status 1, so ignore that failure.
origin_url=`git config remote.origin.url||:`
case $origin_url in
  *[@/]github.com[:/]*)
    github_base_url=`echo "X$origin_url"|sed 's/^X//;s!\([@/]github.com[:/]\).*!\1!'` ;;
  *)
    github_base_url=https://github.com/ ;;
esac
swig_origin_url=${github_base_url}swig/swig.git

if [ -z "$XAPIAN_COMMON_CLONE_URL" ] ; then
    xapian_common_clone_url=.
else
    xapian_common_clone_url=$XAPIAN_COMMON_CLONE_URL
fi

# Set to 'ftp' to use ftp URLs where available and 'http' to use unencrypted
# 'http'.  By default we prefer https downloads as they are more likely to work
# through firewalls and better preserve user privacy.
download_protocol=

# Set to 'always' to always use a locally installed copy of the autotools
# or 'never' to never download.
#
# By default we check for locally installed versions and use them if they are
# new enough versions.  But e.g. for building releases we want to use a known
# set of versions.
download_tools=ifneeded

# Save options which should be sticky for when "make" needs to rerun bootstrap.
# This should be empty or start with a space.
bootstrap_sticky_opts=

while [ "$#" -gt 0 ] ; do
  case $1 in
  --download-tools=*)
    update_bootstrap_sticky_opts "$1"
    download_tools=`echo "x$1"|sed 's/^x--download-tools=//'`
    shift
    continue
    ;;

  --download-tools)
    update_bootstrap_sticky_opts "$1=$2"
    download_tools=$2
    shift 2
    continue
    ;;

  --ftp)
    bootstrap_sticky_opts="$bootstrap_sticky_opts $1"
    download_protocol=ftp
    shift
    continue
    ;;

  --http)
    bootstrap_sticky_opts="$bootstrap_sticky_opts $1"
    download_protocol=http
    shift
    continue
    ;;

  --fetch-url-command=*)
    update_bootstrap_sticky_opts "$1"
    FETCH_URL_TOOL=`echo "x$1"|sed 's/^x--fetch-url-command=//'`
    shift
    continue
    ;;

  --fetch-url-command)
    update_bootstrap_sticky_opts "$1=$2"
    FETCH_URL_TOOL=$2
    shift 2
    continue
    ;;

  --clean)
    # This probably shouldn't be sticky.
    rm -rf INST
    shift
    continue
    ;;

  --without-autotools)
    # This shouldn't be sticky.
    echo "warning: Ignoring old option '$1' - new default is to use installed versions of tools if new enough.  Use '--download-tools=never' to prevent ever downloading"
    shift
    continue
    ;;

  --)
    bootstrap_sticky_opts="$bootstrap_sticky_opts $1"
    shift
    break
    ;;

  -*)
    echo "Unknown option '$1'" 1>&2
    exit 1
    ;;

  *)
    break
    ;;
  esac
done

if [ "$#" -gt 0 ] ; then
  for a in "$@" ; do
    update_bootstrap_sticky_opts "$a"
  done
fi

case $download_tools in
  always|ifneeded) ;;
  never)
    echo "warning: If stuff breaks with '--download-tools=never', you get to keep the pieces"
    ;;
  *)
    echo "Invalid --download-tools value '$download_tools'"
    exit 1
    ;;
esac

[ -d INST ] || mkdir INST
instdir=`pwd`/INST

[ -d BUILD ] || mkdir BUILD
cd BUILD

# The hex strings are SHA256 checksums for the preceding extension.
args='autoconf 2.69'
if need_to_build $args autoconf ; then
  lazy_build $args \
    tar.xz 64ebcec9f8ac5b2487125a86a7760d2591ac9e1d3dbd59489633f9de62a57684 \
    tar.gz 954bd69b391edc12d6a4a51a2dd1476543da5c6bbf05a95b59dc0dd6fd4c2969
  AUTOCONF=$instdir/bin/autoconf
  export AUTOCONF
  AUTORECONF=$instdir/bin/autoreconf
  export AUTORECONF
  AUTOHEADER=$instdir/bin/autoheader
  export AUTOHEADER
  AUTOM4TE=$instdir/bin/autom4te
  export AUTOM4TE
fi
args='automake 1.16.1'
if need_to_build $args automake ; then
  lazy_build $args \
    tar.xz 5d05bb38a23fd3312b10aea93840feec685bdf4a41146e78882848165d3ae921 \
    tar.gz 608a97523f97db32f1f5d5615c98ca69326ced2054c9f82e65bade7fc4c9dea8
  ACLOCAL=$instdir/bin/aclocal
  export ACLOCAL
  AUTOMAKE=$instdir/bin/automake
  export AUTOMAKE
fi
args='libtool 2.4.6'
if need_to_build $args libtool ; then
  lazy_build $args \
    tar.xz 7c87a8c2c8c0fc9cd5019e402bed4292462d00a718a7cd5f11218153bf28b26f \
    tar.gz e3bd4d5d3d025a36c21dd6af7ea818a2afcd4dfc1ea5a17b39d7854bcd0c06e3
  LIBTOOLIZE=$instdir/bin/libtoolize
  export LIBTOOLIZE
  libtool_aclocal=$instdir/share/aclocal
else
  libtool_aclocal=`which libtoolize|sed 's!/bin/[^/]*$!/share/aclocal!'`
  if [ -z "$libtool_aclocal" ] ; then
    echo "libtoolize not found"
    exit 1
  fi
fi

if [ "$1" = "--deps=libmagic" ] ; then
  shift
  lazy_build file 5.3.2 \
    tar.gz 8639dc4d1b21e232285cd483604afc4a6ee810710e00e579dbe9591681722b50
fi

# Save the unadorned aclocal for bootstrapping SWIG.  In particular SWIG
# uses a modified old version of AX_CXX_COMPILE_STDCXX_11 which isn't
# compatible with the current version which might be in a system directory.
SWIG_ACLOCAL=${ACLOCAL-aclocal}

cd ..

# Add -I for in-tree macro directory first, so we use that xapian.m4 in
# preference to one in any directories which may be added below.
ACLOCAL="${ACLOCAL-aclocal} -I `pwd`/xapian-core/m4-macros -I `pwd`/xapian-letor/m4-macros"
export ACLOCAL

aclocal_ac_dir=`${ACLOCAL-aclocal} --print-ac-dir`
aclocal_system_needed=
if [ ! -r "$aclocal_ac_dir/pkg.m4" ] ; then
  if [ -r /usr/share/aclocal/pkg.m4 ] ; then
    aclocal_system_needed=/usr/share/aclocal
  elif [ -r /usr/local/share/aclocal/pkg.m4 ] ; then
    aclocal_system_needed=/usr/local/share/aclocal
  elif [ -r /opt/local/share/aclocal/pkg.m4 ] ; then
    aclocal_system_needed=/opt/local/share/aclocal
  fi
fi

# If the aclocal we're using is in a different prefix to the libtool we're
# using, we probably need to tell aclocal where to look for our libtool's
# macros.  We also need to do this if we add -I /usr/share/aclocal below
# since otherwise the system libtool's macros may be used in preference.
if [ "$aclocal_ac_dir" != "$libtool_aclocal" ] || [ -n "$aclocal_system_needed" ]; then
  ACLOCAL="${ACLOCAL-aclocal} -I $libtool_aclocal"
  export ACLOCAL
fi

# If we're using a non-system automake, check if pkg.m4 is in the directory
# aclocal looks in by default.  If not and there's a system pkg.m4, tell
# aclocal to also look in the system aclocal directory.
if [ -n "$aclocal_system_needed" ] ; then
  ACLOCAL="${ACLOCAL-aclocal} -I $aclocal_system_needed"
  export ACLOCAL
fi

case `${LIBTOOLIZE-libtoolize} --version` in
"")
  echo "${LIBTOOLIZE-libtoolize} not found"
  exit 1 ;;
"libtoolize (GNU libtool) 1.4.*")
  echo "${LIBTOOLIZE-libtoolize} is from libtool 1.4 which is too old - libtool 2.2 is required."
  echo "If you have both installed, set LIBTOOLIZE to point to the correct version."
  exit 1 ;;
"libtoolize (GNU libtool) 1.5.*")
  echo "${LIBTOOLIZE-libtoolize} is from libtool 1.5 which is too old - libtool 2.2 is required."
  echo "If you have both installed, set LIBTOOLIZE to point to the correct version."
  exit 1 ;;
esac

intree_swig=no
modules=
for module in ${@:-xapian-core xapian-applications/omega swig xapian-bindings} ; do
  d=$module
  if [ "$d" = swig ] ; then
    if [ -f "xapian-bindings/.nobootstrap" ] ; then
      # No point bootstrapping SWIG if we aren't going to use it.
      echo "Skipping '$d' due to presence of 'xapian-bindings/.nobootstrap'."
      continue
    fi
    handle_git_external swig "$swig_git_commit_hash" "$swig_origin_url"
  fi
  if [ -f "$d/configure.ac" -o -f "$d/configure.in" ] ; then
    :
  else
    # Skip any directories we can't bootstrap.
    continue
  fi
  if [ -f "$d/.nobootstrap" ] ; then
    # Report why to save head scratching when someone forgets they created
    # a .nobootstrap file.
    echo "Skipping '$module' due to presence of '$d/.nobootstrap'."
    continue
  fi
  case $d in
  xapian-applications/omega|xapian-letor)
    # If someone's created a directory for common, leave it be.
    if [ -h "$d/common" ] || [ ! -d "$d/common" ] ; then
      # Pick omega_common_commit_hash or letor_common_commit_hash:
      var=`echo "$d"|sed 's!.*[-/]!!g'`_common_commit_hash
      hash=`eval echo \\\$"$var"`
      if [ -f .git/shallow ] ; then
	if git reflog "$hash" -- 2> /dev/null ; then
	  : # Already have the desired commit.
	else
	  git fetch --unshallow
	fi
      fi
      handle_git_external "$d/.common.git" "$hash" "$xapian_common_clone_url"
      ln -sf .common.git/xapian-core/common "$d/common"
    fi
    ;;
  esac

  echo "Bootstrapping \`$module'"
  [ -f "$d/preautoreconf" ] && perl "$d/preautoreconf"

  # If we have a custom INSTALL file, preserve it since autoreconf insists on
  # replacing INSTALL with "generic installation instructions" when --force
  # is used.  Be careful to replace it if autoreconf fails.
  if [ -f "$d/INSTALL" ] ; then
    if grep 'generic installation instructions' "$d/INSTALL" >/dev/null 2>&1 ; then
      :
    else
      mv -f "$d/INSTALL" "$d/INSTALL.preserved-by-bootstrap"
    fi
  fi

  autoreconf_rc=
  if [ swig = "$module" ] ; then
    # SWIG provides its own bootstrapping script.
    curdir=`pwd`
    cd "$d"
    ACLOCAL=$SWIG_ACLOCAL ./autogen.sh || autoreconf_rc=$?
    cd "$curdir"
    # Use the uninstalled wrapper for the in-tree copy of SWIG.
    intree_swig=yes
  else
    # Use --install as debian's autoconf wrapper uses 2.5X if it sees it
    # (but it doesn't check for -i).
    #
    # Use --force so that we update files if autoconf, automake, or libtool
    # has been upgraded.
    ${AUTORECONF-autoreconf} --install --force "$d" || autoreconf_rc=$?
  fi
  if [ -f "$d/INSTALL.preserved-by-bootstrap" ] ; then
    mv -f "$d/INSTALL.preserved-by-bootstrap" "$d/INSTALL"
  fi
  if [ -n "$autoreconf_rc" ] ; then
    exit $autoreconf_rc
  fi
  for f in config.guess config.sub ; do
    if [ -f "$d/$f" ] ; then
      update_config "config/$f" "$d/$f"
    fi
  done
  modules="$modules $module"
done

# Produce an absolute path to srcdir.
srcdir_abs=`pwd`

# Generate the top-level configure script.
rm -f configure.tmp
cat <<TOP_OF_CONFIGURE > configure.tmp
#!/bin/sh
# configure each submodule in a xapian source tree
# Generated by Xapian top-level bootstrap script.
#$copyright
trap 'echo "configure failed"' EXIT
set -e

srcdir="$srcdir_abs"
modules="$modules"

TOP_OF_CONFIGURE

cat <<'MIDDLE_OF_CONFIGURE' >> configure.tmp
# Produced escaped version of command suitable for pasting back into sh
cmd=$0
user_CPPFLAGS=$CPPFLAGS
user_LDFLAGS=$LDFLAGS
for a ; do
 case $a in
  *[^-A-Za-z0-9_+=:@/.,]*)
   esc_a=`echo "$a"|sed 's!\([^-A-Za-z0-9_+=:@/.,]\)!\\\\\\1!g'`
   cmd="$cmd $esc_a" ;;
  *)
   cmd="$cmd $a" ;;
 esac
 # Capture any command-line settings of CPPFLAGS or LDFLAGS so we can override
 # for omega.  We follow the behaviour of autoconf-generated configure scripts
 # in that command-line setting beats environment variable setting, and the
 # last of multiple command-line settings is used.
 case $a in
   CPPFLAGS=*)
     user_CPPFLAGS=`expr "x$a" : 'xCPPFLAGS=\(.*\)'` ;;
   LDFLAGS=*)
     user_LDFLAGS=`expr "x$a" : 'xLDFLAGS=\(.*\)'` ;;
 esac
done

here=`pwd`
MIDDLE_OF_CONFIGURE

vars=
if [ yes = "$intree_swig" ] ; then
  # We want the path to SWIG to point into srcdir, which isn't known until
  # configure-time, so we need to expand $here in configure.
  vars=' SWIG=$here/swig/preinst-swig'
elif [ -n "$SWIG" ] ; then
  # User specified SWIG in environment, e.g. with:
  #   SWIG=/opt/swig/bin/swig ./bootstrap
  vars=" SWIG='"`echo "$val"|sed 's/\(['"\\'"']\)/\\\1/g'`"'"
fi
for tool in $autotools ; do
  eval "val=\$$tool"
  if [ -n "$val" ] ; then
    echo ': ${'"$tool='$val'"'}' >> configure.tmp
    echo "export $tool" >> configure.tmp
    vars="$vars $tool='"`echo "$val"|sed 's/\(['"\\'"']\)/\\\1/g'`"'"
  fi
done
if [ -n "$vars" ] ; then
  # $vars will always have a leading space.
  echo "set$vars "'"$@"' >> configure.tmp
fi

cat <<'END_OF_CONFIGURE' >> configure.tmp
dirs=
revdirs=
XAPIAN_CONFIG=$here/xapian-core/xapian-config
XAPIANLETOR_CONFIG=$here/xapian-letor/xapianletor-config
for d in $modules ; do
  if [ "$here" = "$srcdir" ] ; then
    configure=./configure
    configure_from_here=$d/configure
  else
    configure=$srcdir/$d/configure
    configure_from_here=$configure
  fi
  if [ -f "$configure_from_here" ] ; then
    if [ -d "$d" ] ; then : ; else
      case $d in
      xapian-applications/*) [ -d xapian-applications ] || mkdir xapian-applications ;;
      esac
      mkdir "$d"
    fi
    echo "Configuring \`$d'"
    # Use a shared config.cache for speed and to save a bit of diskspace, but
    # don't share it with SWIG just in case it manages to probe and cache
    # different answers (e.g. because it uses a C compiler).
    case $d in
    swig)
      case "$*" in
      *--host=*|*--host" "*)
	# We're cross-building, but SWIG needs to be built natively.
	swig_configure_args=
	skip=
	for arg in "$@" ; do
	  if [ -n "$skip" ] ; then
	    skip=
	    continue
	  fi
	  case $arg in
	  --host=*)
	    # Drop --host=xxx
	    continue ;;
	  --host)
	    # Drop --host xxx
	    skip=1
	    continue ;;
	  CC=*|CXX=*)
	    # Drop CC=xxx or CXX=xxx
	    continue ;;
	  CC_FOR_BUILD=*|CXX_FOR_BUILD=*)
	    # CC_FOR_BUILD=xxx -> CC=xxx; CXX_FOR_BUILD=xxx -> CXX=xxx
	    arg=`echo "$arg"|sed 's/_FOR_BUILD//'`
	    ;;
	  SWIG=*)
	    # Drop SWIG=xxx - not useful and could cause problems.
	    continue ;;
	  esac
	  swig_configure_args="$swig_configure_args "\'`echo "x$arg"|sed "s/^x//;s/'/'\\\\\\\\''/g"`\'
	done
	# Also handle compilers specified in environment variables.  We can
	# just reassign them unconditionally as CC and CXX are ignored if
	# empty.
	cd "$d" && CC=$CC_FOR_BUILD CXX=$CXX_FOR_BUILD "$configure" `eval echo $swig_configure_args`
	;;
      *)
	cd "$d" && "$configure" ${1+"$@"}
	;;
      esac
      ;;
    xapian-core)
      cd "$d" && "$configure" --enable-maintainer-mode --disable-option-checking --cache-file="$here/config.cache" ${1+"$@"}
      ;;
    xapian-letor)
      cd "$d" && "$configure" --enable-maintainer-mode --disable-option-checking XAPIAN_CONFIG="$XAPIAN_CONFIG" --cache-file="$here/config.cache" ${1+"$@"}
      ;;
    xapian-applications/omega)
      cd "$d" && "$configure" --enable-maintainer-mode --disable-option-checking XAPIAN_CONFIG="$XAPIAN_CONFIG" CPPFLAGS="-I$srcdir/INST/include $user_CPPFLAGS" LDFLAGS="-L$srcdir/INST/lib $user_LDFLAGS" ${1+"$@"}
      ;;
    *)
      cd "$d" && "$configure" --enable-maintainer-mode --disable-option-checking --cache-file="$here/config.cache" XAPIAN_CONFIG="$XAPIAN_CONFIG" XAPIANLETOR_CONFIG="$XAPIANLETOR_CONFIG" ${1+"$@"}
      ;;
    esac
    cd "$here"
    dirs="$dirs $d"
    revdirs="$d $revdirs"
  fi
done

case " $* " in
  *" --help "*|*" --version "*)
    # Don't generate Makefile if --help or --version specified.
    trap - EXIT
    exit 0
    ;;
esac

rm -f Makefile.tmp
cat <<EOF > Makefile.tmp
# Makefile generated by:
CONFIGURE_COMMAND := $cmd
EOF
if [ "$srcdir" != . ] ; then
    cat <<EOF >> Makefile.tmp

VPATH = $srcdir
EOF
fi
targets='all install uninstall install-strip clean distclean mostlyclean maintainer-clean dist check distcheck'
for target in $targets ; do
  echo
  echo "$target:"
  case $target in
    uninstall|*clean)
      # When uninstalling or cleaning, process directories in reverse order, so
      # that we process a directory after any directories which might use it.
      list=$revdirs ;;
    *)
      list=$dirs ;;
  esac
  for d in $list ; do
    case $d,$target in
    swig,install*|swig,uninstall)
      # Nothing to do with swig when installing/uninstalling.
      ;;
    swig,dist|swig,check|swig,distcheck|swig,all)
      # Need to ensure swig is built before "make dist", "make check", etc.
      echo "	cd $d && \$(MAKE)" ;;
    swig,mostlyclean)
      echo "	cd $d && \$(MAKE) clean" ;;
    xapian-bindings,distcheck)
      # FIXME: distcheck doesn't currently work for xapian-bindings because
      # xapian-core isn't installed.
      echo "	cd $d && \$(MAKE) check && \$(MAKE) dist" ;;
    *)
      echo "	cd $d && \$(MAKE) $target" ;;
    esac
  done
  case $target in
    distclean|maintainer-clean) echo "	rm -f Makefile config.cache" ;;
  esac
done >> Makefile.tmp
cat <<EOF >> Makefile.tmp

recheck:
	\$(CONFIGURE_COMMAND)

Makefile: $srcdir/configure
	\$(CONFIGURE_COMMAND)

$srcdir/configure: \\
END_OF_CONFIGURE

: > configure.tmp2

# We want to rerun bootstrap if a series file changes (patch added or removed)
# or an existing patch changes.  Since we always have an series file (even if
# it is empty), this also handles us adding the first patch for something.
patches=
for d in patches/* ; do
  series=$d/series
  echo "$series:" >> configure.tmp2
  cat << END
    $series\\\\
END
  sed -n 's/[	 ]*\(#.*\)\?$//;/./p' "$series" |\
      while read p ; do
    patch=$d/$p
    cat << END
    $patch\\\\
END
    # Because there's a pipeline, this is a subshell, so use a temporary file
    # rather than a variable to compile a list of patches to use below.
    echo "$patch:" >> configure.tmp2
  done
done >> configure.tmp

cat <<'END_OF_CONFIGURE' >> configure.tmp
    $srcdir/bootstrap
END_OF_CONFIGURE
echo "	\$srcdir/bootstrap$bootstrap_sticky_opts" >> configure.tmp
cat <<'END_OF_CONFIGURE' >> configure.tmp

.PHONY: $targets recheck

# Dummy dependencies to allow removing patches we no longer need.
END_OF_CONFIGURE

cat configure.tmp2 >> configure.tmp

cat <<'END_OF_CONFIGURE' >> configure.tmp
EOF
mv -f Makefile.tmp Makefile
trap - EXIT
echo "Configured successfully - now run \"${MAKE-make}\""
END_OF_CONFIGURE

rm -f configure.tmp2

chmod +x configure.tmp
mv -f configure.tmp configure

# git defaults to showing 7 character abbreviated hashes if that's enough to be
# unique for a particular commit.  But you can't paste these into trac as it
# needs at least 8 hex digits to recognise a hex string as a commit hash.  You
# need 9 characters to be unique across all of Xapian at the time of writing,
# and 12 for the Linux kernel currently (a much larger number of objects than
# Xapian).  12 is a manageable length and decently future-proof, so let's use
# that.
core_abbrev_recommended=12
core_abbrev=`git config --get core.abbrev||:`
if [ -z "$core_abbrev" ] ; then
  echo "*** Setting core.abbrev=$core_abbrev_recommended in repo config"
  git config --local core.abbrev "$core_abbrev_recommended"
elif [ "$core_abbrev" -lt "$core_abbrev_recommended" ] ; then
  if [ -z "`git config --local core.abbrev`" ] ; then
    # Set globally to < $core_abbrev_recommended, override in this repo.
    echo "*** Setting core.abbrev=$core_abbrev_recommended in repo config to override global core.abbrev=$core_abbrev"
    git config --local core.abbrev "$core_abbrev_recommended"
  else
    # Just warn.
    echo "warning: core.abbrev=$core_abbrev set on this repo, at least $core_abbrev_recommended is recommended"
  fi
fi

trap - EXIT
echo "Bootstrapped successfully - now run \"$srcdir/configure\" and \"${MAKE-make}\""
